Transmission and control mechanism



March 10, 1953 B. ARMITAGE ETAL 2,630,717

TRANSMISSION AND CONTROL MECHANISM Original Filed Jan. 6, 1939 4 Sheets-Sheet l 0 N Q Q N E 5 M Q1 s als r w R IN VEN TOR,

March 10, 1953 J. B. ARMITAGE ETAL 2,630,717

TRANSMISSION AND CONTROL MECHANISM Original Filed Jan. 6, 1939 4 Sheets-Sheet 2 55 w E i Q 5 5 Q: za-

' 1|! 25$ ll i i" :1 al I x is: I i

March 1953 J. a. ARMITAGE ETAL TRANSMISSION AND CONTROL MECHANISM Original Fiied Jan. 6, 1939 4 Sheets-Sheet 3 mi V mm i z a W March 10, 1953 J. B- ARMITAGE ET AL 2,630,717

TRANSMISSION AND CONTROL MECHANISM Original Filed Jan. 6, 1959 4 Sheets-Sheet 4 A v M 4 *l EQ) I Patented Mar. 10, 1953 UNITED STATES PATENT OFFICE SMISSION AND CONTROL MECHANISM Joseph B; Armitage and Theodore F. Eserkaln,

Wauwatosa, Wis., assignors to Kearney & Trecker Corporation, West Allis, Wis., a corporation of Wisconsin (on. vanes;

15 Claims.

This invention relates, generally, to improvements in transmission mechanism and more particularly to improved rate changing and control mechanism for reg-ulatinjg "the operation of machinery.

This specification constitutes a division of application Serial No; 249,554 filed January 6, 1939, that issued February ll, 1947 as Patent No. 2,415,801. 4 I r A general object of the invention is to provide an improved rate changing mechanism for transmitting power, together with "control apparatus for regulating it. 7

Another object or this invention is to provide a more efiicient actuating and controlling apparatus for a machine tool or the like.

Another object is to provide an improved control system for regulating the, rate of relative movement of cooperating machine elements.

Another object is to provide an improved electrical control system for regulating the rate of feeding movement in a machine.

Another object is to provide governing means for regulating the rate of feeding movement in a machine, together with control apparatus adapted to effect reversal in the direction of the feeding movement and operating simultaneously to reverse the action of the rate controlling apparatus. I

Another purpose of the invention is to provide improved transmission and control mechanism, such that the rate of one transmission line may be maintained in exact synchronism with the rate of another line as, for example, to maintain a constant rate in spite of tendency in the second transmissionto vary its, rate, or to duplicate rate variations in the secondtransmission in accordance with rate variations in the first transmission.

A further purpose is to effect an improved transmission and control mechanism including preferred and improved interlocks or interconnections of control mechanism between a plura1- ity of transmission or control portions.

A further object is 11. provide improved means for simultaneous operation 10. clutch devices respectively individual to different portions of a transmission train.

A further object is to provide an improved transmission and control mechanism including a plurality of transmission trains, one of the trains including a stepless rate changer adjusted in response to control mechanism operative at least in part from the other train.

A still further purposeis .gfinerally to simplify 2 and improve the construction and operation of transmission and control means for machines, and still other objects will be apparent from the following description taken in connection. with the claims.

According to this invention, an improved transmission and control mechanism is utilized in a pattern controlled machine tool for forming contoured surfaces, the control means functioning automatically to maintain the rate of relative feeding movement between a forming tool and a workpiece substantially constant regardless of the shape of the pattern being followed. The rate of actual relative feeding movement between the workpiece and the forming tool may be governed in response to variations in the speed of the guiding surface of the pattern at the point of engagement with the follower. Since the speed of the guiding surface at the point engag'ed by the follower roller is the same as the speed of the corresponding point on the worl piece that is engaged by the rotary tool, the speed controlling mechanism may be made di rectly responsive to the peripheral speed of the follower roller, the arangement being such that when the rate of movement or the roller tends to increase, the control mechanism acts to reduce the speed of the driving mechanism effecting the relative feeding movement, or vice versa. By this arrangement, the movement of the pattern and the workpiece is controlled automatically in such manner that the relative feeding rate between the forming tool and the workpiece at the point of contact therebetween is maintained substantially constant to provide a uniform predetermined cutting action regardless of changes in the contour of the surface being formed. The speed control mechanism may be electrically actuated and may be adjusted to provide any desired degree of sensitiveness. To provide for operation of the machine ineither direction, the transmission mechanism includes reversing gearing and the control mechanism is provided with reversing means interacting with the reversing gearing.

The foregoing and other objects of this invention, which Will-.beoomemore fully apparent from the following detailed specification, may be achieved by the particular transmission and control mechanism constituting an, exemplifying embodiment of the invention that ,is illustrated in and described in oonnection with theaccompany ing drawings, in which:

Figure 1 is a view inirqnt elevation of a pattern c t ol e m l n ma h n Q li t t .Lappar tus incorporating the invention in a preferred practical form, parts having been broken away to show some of the controlling mechanism.

Fig. 2 is an expanded, partly diagrammatic plan view showing a mechanica1 transmission mechanism for actuating the various movable elements of the machine, and part of the control mechanism;

Fig. 3 is a schematic circuit diagram of an electrical control system forming part of the control mechanism of the machine;

Fig. 4 is a diagrammatic view of a hydraulic control circuit and some of the apparatus associated therewith for hydraulically controlling the actuation of various parts of the machine;

Fig. 5 is an enlarged detail view of part of the feed rate controlling mechanism, taken generally in horizontal section substantially along the line 55 in Fig. l;

' Fig. 6 is an enlarged view in horizontal section of another part of the feed rate controlling mechanism, taken generally along the line 6--@ in Fig. 1;

Fig. 7 is an enlarged detailed view of an electrical control unit, taken in vertical section along the line ll in Fig. 6;

Fig. 8 is a similar sectional view of the control unit, complementary to Fig. 7 and taken on the same vertical plane but looking in the opposite direction as indicated by the arrows 8-8 in Fig.

6; and

Fig. 9 is another enlarged fragmentary view of the electrical control unit, taken in longitudinal section generally along the line 99 in Fig. 7.

The particular machine illustrated in the drawings as exemplifying apparatus of the class adapted to utilize transmission mechanism constructed and operated in accordance with the principles of the present invention, is primarily a milling machine of the bed type, although it is to be understood that the invention may be applied to other machines of different construction with equal advantage.

Referring more specifically to the drawings, and particularly to Fig. 1 thereof, the milling machine there shown incorporates a practical, operative embodiment of the improved transmission mechanism to which this invention is directed, the entire apparatus being fully described herein by way of a complete disclosure. As there shown, the structure comprises essentially a hollow bed or base 21 that constitutes the foundation or frame of the milling machine forming a housing for the driving mechanism for actuating the various movable parts of the apparatus. The base 2| serves also as a support for a pair of spaced uprights 22 and 23 rigidly mounted at the rear thereof and constituting an upstanding column structure for supporting a bodily movable horizontal tool carrying spindle 24.

On the upper surface of the bed 2! in front of the column structure,is slidably mounted a reciprocating work supporting table or platen 38 guided for movement in a path transverse to the axis of the tool spindle 24. The table 38 rotatably supports a work and pattern carrying spindle 40 which is journalled thereon axially parallel with the tool spindle 24 and carries at its inner end adjacent to the spindle 24 a rotatable work holder or supporting fixture 4| adapted to present workpieces 42 in cooperating relationship with a suitable rotary cutter 43 carried by the tool spindle, as best shown in Fig. 2. At its forward or outer end, the work spindle 40 carries a guiding cam or pattern 44 having its outer edge or periphery contoured in a predetermined manner to present a controlling surface that constitutes a guide for machining the workpieces on the fixture 4! to the desired shape.

For cooperating with the rotary guiding pattern 44, there is provided a tracer element in the form of a follower roller 45 which is journalled in a bracket 46 rigidly mounted on the base 2| in position to be engaged by the periphery of the pattern 4 3 as shown in Fig. 1. The pattern 44 is normally held in contact with the follower roller 45 under a constant yielding pressure by means of a hydraulic piston 48 operating in a cylinder 49 fixed on the frame 2|, as shown in Figs. 1 and 2, the arrangement being such that during a machining operation the piston 48 urges the table 38 to the left as seen in Figs. 1 and 2 thereby holding the pattern against the follower roller and urging the workpieces 42 into cutting engagement with the rotary cutter 43 in such manner that upon rotation of the spindle 40 the table 38 will move to the right or left as may be necessary in effecting reproduction of the contour of the guiding pattern upon the workpieces.

In pattern controlled machines as previously constructed, the cutting action of the cutter upon the workpieces varies considerably with changes in the slope or angle of the contour of the pattern, the actual feeding rate being comparatively slow at some points and very much faster at others depending particularly upon the amount of movement effected by steep elements of the pattern. Accordingly, the speed of'operation of prior machines is necessarily so limited that the maximum feeding rate at the steepest element of the pattern does not exceed that at which the desired degree of finish is attained, with the result that on other elements of the work, the feeding rate is much lower than it should be, the final effect being that the productice capacity of the machine is seriously restricted. 1

In accordance with an important feature of this invention, this limitation upon eficient operation is obviated by controlling the rate of relative feeding movement in manner to maintain it substantiallyconstant, the speed of rotation of the pattern and work carrying spindle dd being varied automatically in such manner that the actual rate of relative feeding movement between the cutter and the surface of the workpiece is maintained substantially constant regardless of the shape of the contour of the pattern being followed. The follower roller 45 is equal in diameter to and disposed coaxially with the cutter l3, and it engages the guiding surface of the pattern 44 in exactly the same manner and at the same angular position that the cutter engages the workpiece. Therefore the rate of movement of the point on the guiding surface of the pattern which engages the follower roller relative to the roller is exactly equal to the rate of movement of the point on the workpiece which is engaged by the cutter 43 relative to the cutter, regardless of angular changes in the position of the contact point. Consequently, to maintain a uniform rate of cutting action, the rate of movement of the point on the pattern which engages the follower roiler may be utilized as the controlling factor and as this rate of movement is transmitted directly to the follower roller, the desired cutting rate may be efiected by maintaining the speed of the follower roller 35 substantially con stant.

To this end, there is provided according to this invention, an improved governing or control mechanism denoted generally by the reference numeral which is actuated by the follower roller t5 and functions to vary the rate of rotation of the work carrying spindle 4t automatlcally in such mannerthat the rate of movement of the guiding surface of the pattern 64 at its point of contact with the follower roller is maintained substantially constant, thereby insuring a substantially uniform rate of cutting action between the cutter 43 and the workpiece.

The mechanism for driving the tool spindle 2t and for turning the work supporting spindle til includes a driving motor 53 (Fig. 3) mounted within the hollow base zl and having on its shaft a pulley 54 connected by belts '55 witha main driving pulley '55, as shown in Fig. 2. The driving pulley 55 is selectively connectlble to a main driving shaftiil by ineansof a friction mainclutch 58 selectively actuated by a hand clutch lever disposed at the front of the machine base (Fig. l) and functioning through suitable connecting mechanism to start or stop the operation of the machine by engaging or disengaging the clutch.

Power for driving the tool spindle 26 is taken from the shaft 5?, as shown in Fig. 2, by means of a spur gear 5! meshing with a similar spur gear 52 that carries a bevel gear 63 which meshes with a cooperating bevel gear 64. The bevel gear 84 is mounted on a shaft 65 that extends to a speed changing mechanism at the left side of machine comprising, in this instance, a pick-oil gear 65 on the shaft iii and a meshing comple mentary pick-off gear 67 on the end of a parallel horizontal shaft t5, the pick-oil gears being interchangeable and reversible in well known manner to provide for driving the spindle at selected constant speed. The shaft 68 extends inwardly to a point beneath the spindle as shown in Fig. 2 and is provided at its inner end with a bevel. gear 68 that meshes with a complementary bevel gear 15 journalled in the bed 2 I. The gear ill has spindled engagement with a vertically dis posed splined shaft l3 which extends upwardly into and is rotatably supported in the column structure, the splined connection permitting vertical adjustment of the spindle without interfer ing with the driving connection. At its upper end within the column, the shaft '53 is provided with a bevelgear 'l i that meshes with a bevel gear it on the end of a horizontally disposed splined shaft is. The shaft 16 is disposed parallel with the spindle'-i and has slidably mounted thereon a spur pinion ll that meshes with a spur gear wheel iii on the inner end of the spindle, the arrangement being such that when the spindle is adjusted axially, the pinion i! will slide along the splined shaft 75 to maintain the driving connection.

Power for driving the work and pattern supporting spindle it is likewise taken from the main driving shaft 5? through the spurv gears GI and at, the gear 52 being fixed on an in-put shaft 52 at one end of a variable speed transmission unit or rate changer 83 which has at its other end an out-put shaft 84. The out-put shaft B l of the transmission unit is provided with a worm that meshes with and drivesa worm wheel fixed on a horizontal shaft 8?,"as shown in Fig; 2. The shaft 8! carries a spurgear (it that meshes with a slidably mounted clutch gear 39 havingclutch teeth which may he engaged selectively with comgear snnie'shes "directlywith' a gear92 ona drivdeserteing sleeve 93 in-ma'nner torotate it in one direction, while the gear 9| meshes with an idler gear 94 that in turn meshes with a gear 9?: on the sleeve 53 for rotating it in the opposite direction.

The sleeve 93 is provided with. an internal spline which slidably engages a splined shaft 91 in manher to provide a driving connection and at the same time to permit endwise movement of the shaft relative to the sleeve. The shaft 9? is journalled in the table 33 for "movement with it and carries a worm .58 that meshes with a cooperating worm wheel 9t on the work and pattern supporting spindle it, the arrangement being such that the spindle til may be driven in either direction r at the rate determined by the transmission unit 83.

As shown in Fig. 2, the table actuating piston dB is provided with a piston rod 104, the rod connected by a rotatable joint or thrust coupling Hi5 directly to the end of the shaft 91 in such manner that pressure exerted upon the piston 53 in either direction causes the piston rod [lit to move the shaft 9'! and consequently the table 38 in the correspondin direction.

The transmission unit or rate changer B3 is preferably of the infinitely variable type capable of effecting stepless change in speed throughout a considerable range of action, adjustment thereof being accomplished by rotation of a speed controlling shaft lot. The operation of the unit may be in accordance with any of several well shown systems, its mechanism being either mechanical, hydraulic, or electrical in character, the particular construction being of no consequence in this instance.

When the machine is in operation, pressure is applied to the piston 43 in the direction to force the tahl 38 to the left thereby engaging the pattern l t with the follower roller 65, as appears in Figs. 1 and 2. As previously explained, the follower roller 65 is equal in diameter to, and is disposed in axial alignment with the cutter 3, the arrangement being such that the follower roller engages the pattern 44 in a position corresponding exactly to that in which the rotating cutter engages the workpiece 42, with the result that the cutter forms on the workpiece a. contour exactly duplicating the guiding surface of the pattern. Since the rate of therelative feeding movement between the workpiece and the cutter at the point of cutting contact is exactly equal to the rate of movement of the guiding surface of the pattern it at the point engaged by the follower roller at, as previously explained, a uniform rate of relative feeding movement between the workpiecetz and the cutter 43, may be maintained by controlling the rate of rotation of the work holding spindle til inresponse to change in the speed of the pattern guiding surface at the point of contact with the follower. Furthermore, since the peripheral speed of the roller equals that of the guiding surface at the contact point, and since rollers of different diameters are utili ed to correspond with cutters of different sizes, the controlling speed for actuating the governing mechanism 523 may be taken from a point on the periphery of the roller or from an auxiliary roller driven by the roller 45.

In the particular construction shown, the govcrning mechanism 59 is so arranged that it is more convenient to take the controlling speed from thesurface of a second orauxiliary roller lid of diameter corresponding-to that of the roller 45 and operatively connected thereto but disposed farther forward on the machine, instead of directly from the follower roller. Accordingly, the roller i It is frictionally engaged by a governing or measuring roller III of predetermined, fixed diameter, which is operatively connected by means of a chain Il2 to drive one rotatable control element IE8 of an electrical rate control unit H3 at speeds varying in accordance with changes in the speed of the pattern surface at the contact point. To provide a standard rate or synchronizing action serving as a basis for establishing the predetermined uniform feed rate, another co-axially disposed rotatable element I09 of the control unit H3 is driven continuously at a selectively predetermined standard speed from the main driving shaft 51, as shown in Fig. 2. For this purpose, a bevel gear H4 is provided on the forward end of the shaft 5'! in position to have meshing engagement with complementary bevel clutch gears II5 and HE and constitutin therewith a reversing mechanism by means of which the direction of rotation of the element I99 may be selected. A clutch collar I ll disposed between the gears H5 and H5 functions to couple one or the other of these gears to a shaft IIB carrying a worm HQ that meshes with a worm wheel iilfl on a shaft iii. The shaft I2I extends to the front of the machine, as appears in Figs. 1 and 2, and drives a rate changing pick-d gear mechanism I22 which is operatively connected by .a chain I23 to drive the standard speed element electrical contact elements I26 and I2? arranged to be engaged alternatively by an intermediate contact element Lt carried by the element 408 of the control unit, which is driven at the variable speed corresponding to that of the pattern contact point. Whenever the speed of the guiding surface of the pattern 44 at its point of engagement with the follower roller d varies from the predetermined relative cutting rate, the roller t5 and the governing roller I! I vary in speed correspondingly, in manner to cause the variable speed element I-Eil carrying the contact I28 to speed up or slow down thereby bringing the contact i228 into engagement with one or the other of the contacts 525 and E2? on the standard speed element i955. This establishes an electrical circuit to control a regulating motor I39 connected to turn the control shaft Hit of the variable speed transmission mechanism 83, the motor functioning to so adjust the mechanism that the speed of rotation of the work and pattern carrying spindle is either increased or decreased sufiiciently to reestablish and maintain constant the predetermined rate of relative feeding movement between the workpiece "i2 and the cutter 43. This regulation of the feeding rate results in a uniform cutting action between the cutter 33 and the workpiece which may be established, by adjusting the rate changer I22, at such rate that the cutter operates most efficiently at all times and, coincidentally, effects a finished surface of predetermined uniform character on all parts of the work- Since the cutting or feeding rate is controlled by the rate of rotation of the measuring roller i i, and since the rate of rotation of the measuring. roller is directly responsive to the linear velocity of the guiding surface at the point of contact with the follower, the controlling action is not dependent upon the diameter of a particular follower roller nor upon the shape of the pattern. Accordingly, the established feed rate remains constant at its predetermined value regardless of the 'fact that follower rollers of different diameters may be utilized .to correspond with various cutters or that the pattern may be changed for one of a difierent contour. By reason of this arrangement, the actual feed rate may be predetermined accurately in the usual manner merely by inserting appropriate pickoff gears I3 I, I32, I33 and I34 in the speed changing gear mechanism I22, in accordance with the indications of a feed rate chart or other well known means. Consequently, the desired feed rate may be established in advance at that best suited to the conditions of the work, in order to obtain the maximum rate of machining action consistent with the desired degree of finish, regardless of the shape or size of the pattern or the diameter of the cutting tool and follower roller.

The hydraulic pressure for acting upon the piston 48 to retain the pattern 44 in contact with the follower roller 45 as previously described, is derived from a pump l iil represented diagrammatically in Fig. 4. As indicated in the hydraulic circuit diagram, the pump E40 forces liquid under pressure through a conduit I 4| and a branch conduit I42 to a port I43 in a valve casing I44 which is then in communication with a port M5 through which the pressure liquid flows into a conduit I46 leading to the right end of the cylinder 49, thereby exerting pressure to the left upon the piston 48 and urging the table 38 to the left to engage the pattern with the follower roller as previously explained.

In order to retract the pattern and workpiece from engagement with the follower roller and the cutter respectively, as may be required to permit changing the workpiece or for substituting a difierent pattern, a control lever I48 mounted on the front of the machine, as shown in Fig. 1, may be moved to the right, thereby moving a valve plunger I49, to which it is operatively connected, to the right within the valve casing M34, as viewed in Fig. 4. This movement results in the plunger disconnecting the port I43 from the port I45 leading to the right end of the cylinder 49 and establishing a connection between the port !43 and a port I5I which communicates with a conduit I52 leading to the left end of the cylinder. Pressure exerted through the conduit I52 upon the left face of the piston 48 thereupon causes the work-carrying table 38 to move to the right, the liquid in the right end of the cylinder 49 escaping through the conduit I46 and the port I45 which is then open to atmosphere through the left end of the valve casing I 44.

After the required adjustments to the pattern and workpiece have been effected, the table 38 may be advanced to the left into the zone of cutting action to reengage the workpiece with the cutter 43; this is selectively accomplished by moving the control lever I48 to the left to the position shown in Figs. 1 and 4. This reestablishes the flow of pressure liquid through the ports I43 and I45 and the conduit I46 into the right end of the cylinder 49 in manner to move the piston 48 and the table 38 to the left at a rapid rate. The liquid in the left end of the cylinder then escapes by way of the conduit I52 and a conduit I56 through an exhaust valve I51 and a conduit I58 to a port I59 in the valve casing I44, which is then open to atmosphere through the right end of the valve casing.

.machine, as shown in Fig. 1.

'ing opposite sides of the clutch gear 89.

9 Since the cutter ,of'jthe workpieces might be damaged if they were brought together at the rapid rate of movement of the table, means are provided for controlling the escape of exhaust liquid to reduce the rate of movement to a predetermined feed rate just prior to the engagement, thereby avoiding shock. For this purpose, the exhaust valve i? is provided with a spring urged plunger I6I carrying on its outer end a shoe I82 presenting an angular face which is disposed to be engaged by one edge of the pattern 48 and moved side and inwardly as shown in Figs. 4 and 5, as the pattern moves into engagement with the follower roller 45. As

shown, the valve plunger I'fijI thereupon closes the passageway through the. exhaust valve I51 and prevents further escape of liquid through the conduit I58 and the open port I59. The liquid remaining in, the cylinder 49 is then restricted to escape through the conduit I52 and the port IEI which is then in communication with a port I63 connected with a conduit 56:! leading to an adjustable feed rate throttle valve I85. The throttle valve I65 permits the escape of exhaust liquid at a restricted rate to limit further movement of the workpiece toward the cutter to a predetermined relatively slow feed rate. After the workpiece is brought into contact with the cutter, a steady force, is exerted upon the piston t8 by the full pressure of the liquid, the pressure being determined by the setting of an adiustable relief valve: I55.

When it is desired] to reverse the direction of rotation of the worksupporting spindle 48 in order to eilect the cutting action in the opposite i direction, the reverse clutch gear as in the driving mechanism may be shifted by means of a reverse lever I68 mounted on the front of the As appears in Fig. 4., the lever I68 is connected to actuate a sliding control. rod I69 which moves a shifting fork I10 slidably mounted on a guide rod Ill and engag- To disconnect the driving mechanism from the spindle 48, the lever 568 may be moved to the vertical position shown in Figs. 1 and 4, the clutch gear 58 then being in neutral position between the clutch gears 98 and 9% and disengaged from both of them. as shown. When the lever is moved in either direction to either of the operating positions indicated by the dotted circles in Fig. 4, the clutch gear 88 is moved into engagement with either the clutch gear 86 or the clutch gear 9| to effect turning movement of the spindle 40 in th ne or the other direction.

When the direction of rotation of the spindle 5 4D is changed, the variable s eed element I 88 of the electrical control unit I I3 is driven in the opposite direction by the governing roller III and the connecting chain H2. Consequently, in

order to obtain the required synchronizing ac- -tion, the direction of rotation of the standard speed element I09 must be reversed also. This is effected simultaneously with reversal of the spindle 40 by hydraulically actuated means for shifting the clutch sleeve II! of the bevel gear reversing mechanism. As appears in Fig. 4, the reversing control rod IE9 is provided at one end with a valve plunger I13 which operates in a valve casing I14 and functions to connect the pressure conduit I-II alternatively to a conduit H5 or a conduit H6 which. lead to cylinders Il and I18, respectively. The cylinders I I1 and I78 engage opposite ends. of. a, piston element 119 carrying a. shifting fork. I88 that engages the clutch collar III, the arrangement being such that the collar II! is shifted hydraulically in synchronism with the clutch gear 89 to reverse the standard speed element of the control unit H3 at the same time that the variable speed element is reversed.

By reason of the hydraulic interconnection between the reversers, manual engagement of clutch gear 89 with either of its cooperating clutch gears is not interfered with in the event that the ends of the clutch teeth on the clutch collar III abut with the ends of cooperating clutch teeth on the ear H5 or the gear IIB. In such case, the clutch gear 89 is free to move into full engagement with its cooperating clutch gear and the hydraulic pressure exerts a continuous force upon the collar III for moving it into engaged position as soon as its teeth are turned to mesh with the cooperating clutch teeth.

When the direction of rotation of the variable speed element I08 of the control unit IIS is reversed in consequence of reversing the direction of rotation of the spindle 40, the action of the two contact elements I26 and I27 of the standard speed element I09 is likewise reversed, since the opposite one of these contacts will then be engaged by the intermediate contact I28 whenever excessive speed is transmitted from the pattern to the variable speed element I08, and vice versa. Accordingly, the electrical connections from the contacts I26 and I2! to the regulating motor I30 must be correspondingly reversed by action of the reversing lever I66. For this purpose there is provided a pair of circuit reversing switches IBI and I82 which are associated with and actuated by the reversing lever I68, the arrangement being such that both switches are in the open position when the lever is in neutral, as is shown in the wiring diagram, Fig. 3.

Electrical energy for energizing the main motor 58 and the speed controlling motor I 38 is derived from line conductors L1, L2 and L3 through a main starting switch I83, as shown in Fig. 3. Assuming now that the work spindle reversing lever IE8 is moved to the right thereby closing the circuit reversing switch I82 for conditioning the control system. to operate in a me determined direction, a circuit is established from the line conductor L1 through the motor starting switch I83, a supply conductor S1, a conductor I84, the closed s witch I82, a conductor I85, the solenoid of a relay I86, and thence through a conductor I81, to a supply conductor $2, the switch I 88 and the line conductor L2, thereby closing the relay I 86. This establishes connections with the contacts I26 and I 21 of the standard speed element I09 for controlling the speed regulating motor I38 during operation of the'spindle in the direction corresponding to the position of the lever I68. Either one of the contacts I26 or I27 may now be energized for controlling the motor I30 by contact with the variable speed contact I28, which is connected by a conductor I38 and a supply conductor S3 to the switch 183 and the third line conductor L3. When the variable speed contact I28 is moved into engagement with one of the standard speed contacts, the contact I26, for example, a circuit is completed from supply conductor S3 through conductor use, and the contact I28, to the contact I26, thence by a conductor I90, the closed relay 18 a conductor I9I, and a conductor I92 to the solenoid of an electrically operated motor reversing switch the switch I93.

11 I93, and thence through a conductor I94 to the supply conductor S2, thereby closing the switch I93.

With the switch I93 closed, three-phase current for actuating the motor I32 in a predetermined direction is drawn from the line conductors L1, L2 and L3 through the switch I83 and the supply conductors S1, S2 and S3 as follows. From the supply conductor $1, a conductor I96 leads to a conductor I91 which is connected by the closed switch I93 to a conductor I98 that connects with a conductor M1 leading to the motor I39. From the supply conductor S3, the circuit leads through a conductor 2M that is connected by the closed switch I93 to a conductor 292, and thence by a conductor M3 leading to the motor. From the supply conductor S2, the circuit leads through the conductor I94, a conductor 294, and interrupting switches 2G5 and 295, to a conductor M2 leading to the motor. The motor I39 then operates to adjust the transmission mechanism 83 until the predetermined feed rate is reestablished, whereupon the contacts I28 and I26 move out of engagement and the motor stops.

When the variable speed contact I29 is moved into engagement while the other standard speed contact I21, with the lever N38 is permitted to remain in the same position, a different circuit is completed, leading from the supply conductor S3 through the conductor I83 and the a contact I28 to the contact I21, and by a conductor 2 III, the closed relay I86, a conductor 2H- and a conductor 2I2 to the solenoid of another motor reversing switch 2 I 3 and thence by a conductor 2I4 to the supply conductor S2, thereby closing the switch 2I3. With the switch 2! 3 closed, the supply conductor S1 is now connected, by the conductor I96 and the switch 2I3, to a conductor 293 and the motor conductor M3;

and the supply conductor S3 is connected through the conductor 2I'II, a conductor 2I5 and the switch 2 I3 to a conductor 2 I6 and the'motor conductor M1 thereby interchanging two phases of the motor circuit and causing the motor to operate in a direction opposite from that in which it operates when the contact I29 is enaged and the switch I93 is closed.

If the lever I69 is now moved to the left to actuate the spindle II} in the opposite direction, the circuit reversing switch I 82 is opened and the circuit reversing switch Isl is closed, thereby deenergizing the solenoid of the relay I95 and establishing a circuit from the supply conductor S1 through the conductor I341, the closed switch I8I, and a conductor 2H to the solenoid of another relay 2I8 and thence to a conductor 2It which connects with the conductor I 87 leading to the supply conductor 82. This results in opening the relay I 99 and closing the relay 2 I 8. With the relay 2I9 closed, the contacts I25 and I2? on the constant speed element I99 are connected to the solenoids of the motor reversing switches in opposite manner, so that the contact I29 controls the motor reversing switch 2I3 while the contact I2'I controls the motor reversing switch I93. As shown, the circuit from the contact I25 then extends through the conductor I99 and a conductor 229 to the closed relay 2I8 and thence to the conductor 2I2 which leads to the solenoid of the switch 2I3. The circuit from the contact I2? then extends through the conductor 2 III and a conductor 22 I to the closed relay 2 I I3 and thence to conductor I92 which leads to the solenoid of If the variable speed contact I29 is then moved into engagement with either of the contacts I29 or I21, a regulating efiect opposite to that previously described is obtained. By this arrangement, the action of the variable speed transmission regulating motor I39 is so controlled as to compensate for variations in the speed or" the guiding surfaces of the pattern i lin the correct direction regardless of the direction of rotation of the pattern.

Although the described control system is illustrated as functioning to maintain the cutting action of a pattern controlled machine tool substantially constant at the most effective feed rate, as predetermined by adjustment of the rate changing mechanism, it is to be understood that the speed controlling system may be used to advantage in effecting speed control for various other purposes. Furthermore, it may be adapted to effect variable speed operation of one machine element in accordance with the varying speeds of another machine element or in accordance with the speeds established by a controlling element operative to efiect a predetermined speed changing sequence.

The two movable elements I08 and I63 of the electrical control unit II3 each comprises a body portion preferably formed of insulating material as indicated in Figs. 3, 6 and 9 of the drawing. As shown, the variable speed element I98 of the unit II3 comprises a plate or disc 225 of insulating material carrying on its periphery a slip ring 2.21 which is electrically connected to the intermediate contact element I28, and which is mounted on the face of the disc, a brush 222 being provided in slidable contact with the ring for establishing connection between it and the control conductor I88. The constant speed element I99 of the control unit comprises a cylinder 239 of insulating material carrying the contact elements I26 and I2! in arcuately spaced relation on its forward face and having on its periphery a pair of spaced slip rings 29! and 232 electrically connected with the contacts I2 and I2? respectively, as shown in Figs. 3 and 9, and slidably engaged by brushes 234 and 235, respectively connected to the control conductors I92 and 2III.

As appears in Figs. 6, '7 and 8, the several brushes 221, 234 and 235 are mounted, by means of insulating supports, on the interior of a housing 236 formed in the front of the machine bed 2I and arranged to enclose the rotating elements of the electrical control unit II3. As shown in Figs. 6 and 8, the variable speed element I98 is carried by a relatively light shaft 23'I extending through the insulating disc 225 and supported at its ends on pivot points for free rotation, its for ward end carrying a sprocket wheel 238 which is engaged by the driving chain I I2. The chain II2 extends upwardly from the sprocket 238 within a hollow arm or bracket 24%] that is pivotally mounted on the front of the machine ooaxially with the shaft 231 as shown in Figs. 1 and 6. At its upper end, the arm 249 carries the governing roller III, as shown in Fig. 5, the roller being fixed on a shaft 24I mounted on pivot points for free rotation and that carries a sprocket 242 which engages the chain II2 extending upward from the sprocket 238. The chain II2 thereby effects a driving connection between the roller I I I and the variable speed element I98, the arrangement being such that the roller and the variable speed element rotate freely and in synchronism in manner to respond quickly and accurately to the slightest change in the speed of rotation ofthefollower-roller 45 and the corresponding roller H0.

As appears in Fig. 5, the follower roller 45 and the corresponding roller Hi3 are removably mounted on opposite ends of a short shaft 255 journalled in the bracket t6, the arrangement being such that both of these rollers may be removed readily whenever the cutter 43 is changed in order that they may be replaced by rollers corresponding exactly in diameter to the diameter of the new cutter thereby maintaining the predetermined relationship between the pattern and the speed controlling mechanism. The governing roller Ill, being mounted on the upper end of the pivoted arm 246, may be adjustably positioned to engage with a roller Ht of any diameter, and a spring urged plunger 2%, mounted on the front of the machine as shown in Figs. 1 and 5, is disposed to engage the arm Mill in manner to press the governing roller 1 ll into contact with the roller [ill with sufficient force to establish frictional driving connection between them. Although in the particular construction shown, it is preferable to utilize the auxiliary corresponding roller Hi3, it is to be understood that the governing roller H! may be applied directly'to the periphery of the follower roller 35 whenever the construction of the machine favors that arrangement.

The insulating cylinder 23B of the standard speed element Hi9, which carries the contacts 26 and i2? of the control unit H3, is mounted on the forward end of a shaft 250 journalled in the rear wall of the housing 235, as shown in Fig. 6. At its inner end, the shaft 258 is operatively connected, by means of a torque limiting coupling or slip clutch 25L to a sprocket 282 which is driven from the rate changing mechanism 22 at the predetermined standard rate by means of the chain I23.

In order to control the sensitivity of response of the electrical control unit Hit, the contact i'Zt of the constant speed element its is adjustably mounted for arcuate movement relative to the contact iZ'i along the face of the insulating cylinder 2351, by means of a retaining bolt 254 operating in a slot 255, as shown in '7. By moving the contact I26 close to thecontact 21, the range of movement of the intermediate contact 23 may be so reduced that the slightest variation. in the speed of the. element H38 from that of the constant speed element its causes the contact 23 to engage one or the other of contacts I23 and 12?, whereby very close regulation H of the speed changing transmission mechanism may be achieved, if desired. On the other hand, should it be considered desirable that the regulating motor 436 be energized less frequently in effecting the regulating operation, the contact 926 may be set farther from the contact l2! to afford a greater range of movement to the intermediate contact I28.

In the event that the driving action of the governing roller ill should be discontinued, either through moving the pattern a l out of engagement with the follower roller 65 or through disconnecting the work spindle drive by moving the reversing clutch gear 89 to neutral position, while the constant speed element H39 of the control unit continues to rotate, one of two conditions will result; either the variable speed element H18 and the governing roller ill will be driven by the rotating element 109, or, should the roller Ill be prevented from turning by engagement of the pattern 44 with the follower roller or like reason, the overload clutch $255 will slip, thereby preventing excessive torque from being imparted to the control unit. Under either of these conditions, the contact I28 will remain engaged with either the contact 12s or i2! and the regulating motor We will tend to run continuously until the speed changing mechanism 83 has been adjusted to one or the other extreme position, whereupon the motor its will stall if not otherwise stopped.

Since unintentional adjusting oi the mechanism 83 to an extreme position is undesirable, the previously mentioned interrupting switch 2% is arranged to be actuated by the plunger E35 of the exhaust valve as shown in Figs. l and 5, in such manner that whenever the pattern M moves out of contact with the follower roller 55 the switch 295 will be opened, thereby deenergizing the motor its and preventing it from operating in response to engagement of the contacts in the control unit. Likewise, the motor Ltd is deenergized whenever the driving connection to the pattern id is disconnected by moving the reversing clutch gear to the neutral position, since both of the reversing switches l8; and are then moved to a disengaged position, as indicated in Figs. 3 and 4, thereby deenergizing the relays I36 and 21B and disconnecting the control unit i i3 from the switches controlling the motor I30.

Furthermore, the other previously mentioned interrupting switch 296 is arranged to be actuated by the main clutch lever 59, as shown in Fig. l, the arrangement being such that when the lever 52 is positioned to disengage the main clutch 53 thereby stopping the work spindle ill, the switch 2555 is opened to deenergize the motor its to prevent its operation should the contacts remain in an engaged position. Likewise, when the machine is stopped by opening the motor switch I83, the regulating motor i558 is automatically deenergiae-d and prevented from shifting the speed changing adjusting mechanism to an extreme position, since both the main motor and the regulating motor are energized from the line conductors L1, L2 and L3 through the main switch.

From the foregoing description of the construction and operation of an illustrative machine tool transmission mechanism Operating in accordance with the principles of this invention, it is apparent that there has been provided improved transmission and control apparatus that functions to regulate the relative feeding movement of a workpiece and a work forming tool or similar members automatically in such manner as to effect the most efiicient operation of the tool and to form on the workpiece a finished surface of uniform character throughout.

Although the foregoing detailed description and the accompanying drawings are directed epoch? ically to particular apparatus exemplifying a preferred construction for the purpose of fully disclosing an operative embodiment of the in vention, it is to be understood that the particular structure shown and herein described is intended to be illustrative only, and that various featiu'es of the invention may be incorporated in other forms and constructions Without departing from the spirit and scope of the invention as defined in the subjoined claims.

The principles of the embodying apparatus having now been fully explained, we hereby claim as our invention:

1. In a rate control mechanism for a transmis- Y sion including an adjustable rate changer, the

combination of power operable adjusting means for said rate changer, a rate control ,rain, a plurality of co-axial elements respectively r tatable through said rate control train and through rate changer, and means controlling the power operation of said adjusting means in accordance with the relative rotational displacements of said co-axial elements.

2. In a rate control mechanism for a transmission train including an adjustable rate changer and a shiftable motion interrupter, the combination of power operable adjusting means for said rate changer, a rate control train, means normally controlling the power operation of said adjusting means in accordance with the rate of said rate control train, and control means operatively connected to interrupt the operation of said adjusting means whenever said motion interrupter is moved to its interrupting position.

3. In a rate control mechanism for a transmis sion train including an adjustable rate changer, the combination of power operable means for adjusting said rate changer, a rate control train including a shiftable reverser, means reversibly controlling the power operation of said adjusting means in accordance with the rate of said rate control train, and means reversing the direction eiiect of said controlling means simultaneously with the shifting of said reverser.

4. In a speed regulating system, the combination with relatively movable elements, of a controllable variable speed transmission mechanism operatively connected to eifect relative movement of said elements, an electrical contact member operatively connected to move in accordance with the speed of said relative move ment, a cooperating electrical contact member operatively connected to be driven at a predetermined governing speed, and means responsive to cooperation of said contact members to control said variable speed transmission mechanism in manner to maintain said relative movement at a substantially constant predetermined speed.

In a machine, the combination with members arranged for relative movement, of transmission mechanism for effecting relative movement of said members selectively at feed rate or at rapid traverse rate, a second transmission mechanism for effecting relative movement of said members at a governed feeding rate, means to regulate said second transmission mechanism automatically, and means operative when said first transmission mechanism is effecting movement at rapid traverse rate to prevent operation of said automatic regulating means for governing said second transmission mechanism.

6. In a machine, the combination with rela tively movable elements, of a variable speed drive mechanism for effecting relative movement be tween said elements, governing means for controlling said variable speed drive mechanism to regulate the rate of said relative movement automatically, means for reversing the direction of operation of said drive mechanism, means for reversing the effect of said governing means, and a control system operative to actuate simultaneously said drive mechanism reversing means and said governor reversing means.

7. In a machine, the combination with a plurality of members arranged for relative movement, of means for effecting relative feeding movement between said members, a pattern and cooperating follower operatively arranged to guide said relative feeding movement, a control element operatively connected to rotate in accordance with the linear speedof the guiding surface of said pattern, a cooperating control element arranged to rotate at a preselected standard speed, a rate changing mechanism operatively connected to drive said standard speed element and adjustable to select said standard speed, and control means responsive to variations in the relative speed of rotation of said control elements and operative to govern said relative feeding rate in accordance with the adjustment of said rate changing mechanism.

8. In a rate control mechanism for a transmission including an adjustable rate changer, the combination of power operable adjusting means for said rate changer, a rate control train, a plurality of rate control elements respectively rotatable through said rate control train and through said rate changer, a plurality of shiftable reversers respectively operable for reversal of rotation of difierent of said elements, means controlling the power operation of said adjusting means in accordance with the relative rotational displacement of said elements, and means for simultaneously shifting said reversers.

9. In a rate control mechanism for a transmission including an adjustable rate changer, the combination of power operable adjusting means for said rate changer, a rate control train, a plurality of co-axial elements respectively rotatable through said rate control train and through said rate changer, and means reversibly controlling the power operation of said adjusting means including electric circuit means having contacts rcspectively associated with different of said coaxial elements, and electrical reverser means operable from said contacts.

10. In a rate control mechanism for a transmission train including an adjustable rate changer and a reverser, the combination of power operable means for adjustment of said rate changer in opposite directions, reversibly operable means for controlling the power operation of said adjusting means, and means for reversing the direction effect of said controlling means in accordance with the shifting of said reverser, whereby to maintain the same direction effect of said rate changer adjusting means in either direction position of the reverser.

11. In a rate control mechanism for a transmission train including an adjustable rate changer and a reverser, the combination of a rate control train including a reverser, power operable adjustin means for said rate changer, means for simultaneously shifting said reversers to effect corresponding direction positions thereof, reversibly operable means controlling the power operation of said adjusting means in accordance with the rate of said rate control train, and means for reversing the direction effect of said controlling means simultaneously with the shifting of said reversers.

12. In a control mechanism for a transmission comprising a plurality of power trains each including a shiftable positive-type reverser, the combination of manual means for positive shifting of the reverser of one of said trains, impositive power means for shifting another reverser in. another of said trains, and means controlling said impositive power means in accordance with operation of said manual means whereby to effect corresponding simultaneous direction positions of the shifted reversers.

13. In a control mechanism for a transmission comprising a plurality of power trains each including a positive-type reverser, the combina-' tion of manual means for effecting the one or the other direction position of one of said reversers, a fluid operable piston device for shift-,- ing the other reverser, a reverser valve for said piston device shiftable for effecting the one or the other direction position of said other reverser, and means connecting said reverser valve for operation from said manual means to effect simultaneous corresponding direction positions for both said reversers.

14. In a transmission mechanism, a plurality of gear driving trains, a rate adjustor included in one of said gear driving trains, a, reversible type clutch in each of said gear driving trains, interlinking means controlling said clutches for substantially simultaneous operation, a regulat ing mechanism comprising a plurality of ro tatable elements driven by one of said gear trains and by said rate adjustor respectively, power operable adjusting means for said rate changer, and means controlling said rate chan adjusting means in accordance with the relative rotational speed of said rotatable elements in said regulating mechanism.

15. In a machine transmission, an adjustable rate changer, a power actuator arranged to automatically control said rate changer, a governing mechanism comprising coaxially rotatable discs, a plurality of gear trains connected to drive said rate changer and one of said governing mechanism discs respectively, a reversible type clutch in each of said gear driving trains, interlinking control means actuatable' for con joined clutch operation to effect a substantially simultaneous reversal of said gear trains, a secondary driving means connected to rotate nother of said governing mechanism discs through said rate adjustor at a predeterminately variable rate, and control means adapted to control said rate changer power actuator in accordance with the relative speed difierential of said rotatable discs in said governing mechanism.

JOSEPH B. ARMITAGE. THEODORE F. ESERKALN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,994,773 Lapsley Mar. 19, 1935 2,014,632 Padgett Sept. 17, 1935 2,026,827 Dillon Jan. 7, 1936 2,214,986 Barnes Sept. 17, 1940 2,245,017 Sinclair June 10, 1941 2,250,656 Schjolin July 29, 1941 2,267,464 Iavelli Dec. 23, 1941 2,322,479 Schjolin June 22, 1943 2,380,677 Schjolin July 31, 1945 2,401,803 Turchan et a1 June 11, 1946 2,417,780 Parvin Mar. 18, 1947 

